This invention is directed to a system for the gravitational separation of fluids, and to a particular arrangement for determining the current condition of settlement of suspended matter, including sensing the location of any inter-face present in a settlement tank between substances of significantly differing densities, including at least one fluid.
The separation of mechanical mixtures of material suspended in a fluid or in a mixture of fluids, plays an important part in a number of processes, both in industry and society, ranging from the separation of mining slime fluids to the separation of sludge from water in sewage farms.
In many primary ore extraction industries gravitational separation in settling tanks plays a significant part in the total process. Ore slime slurry for instance must be separated from the parent fluid by way of decanting from within the settlement tank before the leaching process can be initiated. Similarly in other well known and widely used processes it is important to be able to effect gravitational separation of predetermined constituents from a finely divided mixture.
It will be understood that the need for gravitational separation arises from the mechanical mixing of two mutually chemically inert substances comprising at least one liquid, having significantly different densities.
The capital costs of settlement tanks are such that any improvement in the utilization of such tanks by effective reduction of residence time within the tank to effect settling can have significant economic benefits.
It will be understood that such mixtures may include liquids and finely divided solids, which can be considered under certain conditions as `fluids.`
Attempts have been made in the past to monitor the constituency of the parent fluid, from which the more dense other component is settling. Thus, ultrasonic and radio-active generators operating through ports in the walls of the tank at predetermined levels are known. Also, probes of the on-off type to determine variations in electrical resistivity or specific heat transference rates have been considered, with no known market effect.